When a regular lock is held, SSI can use that in lieu of a predicate lock
to detect rw conflicts; but if the regular lock is being taken by a
subtransaction, we can't assume that it'll commit, so releasing the
parent transaction's lock in that case is a no-no.

Kevin Grittner

This fixes a pg_upgrade bug that could lead to query errors when clog
files are improperly removed.

As noted by Thom Brown, this confuses the DocBook index processor; it
fails to merge entries that differ only in whitespace, and sorts them
unexpectedly as well.  Seems like a toolchain bug, but I'm not going to
hold my breath waiting for a fix.

Note: easiest way to find these is to look for double spaces in HTML.index.

Per a discussion with Gavin Flower.  This barely scratches the surface
of potential WITH (something RETURNING) use cases, of course, but it's
one of the simplest compelling examples I can think of.

Jan Urbański

Some versions of xcopy, notably on Windows 7 don't like it. Backpatch
to 8.3, where we first used xcopy.

If we call hash_search() with HASH_ENTER, it will bail out rather than
return NULL, so it's redundant to check for NULL again in the caller.
Thus, in cases where we believe it's impossible for the hash table to run
out of slots anyway, we can simplify the code slightly.

On the flip side, in cases where it's theoretically possible to run out of
space, we don't want to rely on dynahash.c to throw an error; instead,
we pass HASH_ENTER_NULL and throw the error ourselves if a NULL comes
back, so that we can provide a more descriptive error message.

Kevin Grittner

Remove the hard-wired assumption that __mips__ (and only __mips__) lacks
dlopen in FreeBSD and OpenBSD.  This assumption is outdated at least for
OpenBSD, as per report from an anonymous 9.1 tester.  We can perfectly well
use HAVE_DLOPEN instead to decide which code to use.

Some other cosmetic adjustments to make freebsd.c, netbsd.c, and openbsd.c
exactly alike.

This used to work, but since PGCLIENTENCODING is now a connection
option variable, pg_upgrade would prevent it.

The original coding supposed that a dump TOC file could never contain lines
longer than 1K.  The folly of that was exposed by a recent report from
Per-Olov Esgard.  We only really need to see the first dozen or two bytes
of each line, since we're just trying to read off the numeric ID at the
start of the line; so there's no need for a particularly huge buffer.
What there is a need for is logic to not process continuation bufferloads.

Back-patch to all supported branches, since it's always been like this.

This is needed only in 9.1 because only 9.0 had this and no one is
upgrading from a 9.0 beta to 9.0 anymore.  We basically don't backpatch
9.0 beta fixes at this point.

in pg_upgrade.

Previous patches took care of assorted places that call transformExpr from
outside the main parser, but I overlooked the fact that some places use
transformWhereClause as a shortcut for transformExpr + coerce_to_boolean.
In particular this broke collation-sensitive index WHERE clauses, as per
report from Thom Brown.  Trigger WHEN and rule WHERE clauses too.

I'm not forcing initdb for this fix, but any affected indexes, triggers,
or rules will need to be dropped and recreated.

The previous functions of assign hooks are now split between check hooks
and assign hooks, where the former can fail but the latter shouldn't.
Aside from being conceptually clearer, this approach exposes the
"canonicalized" form of the variable value to guc.c without having to do
an actual assignment.  And that lets us fix the problem recently noted by
Bernd Helmle that the auto-tune patch for wal_buffers resulted in bogus
log messages about "parameter "wal_buffers" cannot be changed without
restarting the server".  There may be some speed advantage too, because
this design lets hook functions avoid re-parsing variable values when
restoring a previous state after a rollback (they can store a pre-parsed
representation of the value instead).  This patch also resolves a
longstanding annoyance about custom error messages from variable assign
hooks: they should modify, not appear separately from, guc.c's own message
about "invalid parameter value".

This mimics the traceback information the Python interpreter prints
with exceptions.

Jan Urbański

When we release and reacquire SerializableXactHashLock, we must recheck
whether an R/W conflict still needs to be flagged, because it could have
changed under us in the meantime.  And when we release the partition
lock, we must re-walk the list of predicate locks from the beginning,
because our pointer could get invalidated under us.

Bug report #5952 by Yamamoto Takashi.  Patch by Kevin Grittner.

Gabriele Bartolini

Erik Rijkers

Joey Adams, per gripe from Ramanujam.  Review by myself and Tom Lane.

Also avoid hardcoding the current default state by giving it the name
"on" and replace with a meaningful name that reflects its behaviour.
Coding only, no change in behaviour.

Per Robert Haas

This means one less thing to configure when setting up synchronous
replication, and also avoids some ambiguity around what the behavior
should be when the settings of these variables conflict.

Fujii Masao, with additional hacking by me.

This improves compatibility with external toolchains, such as those used
by some documentation translation tools.

Gabriele Bartolini

KaiGai Kohei

Dan Ports

The previous coding set attinhcount too high in some cases, resulting in
an undumpable, undroppable column.  Per bug #5856, reported by Naoya
Anzai.  See also commit 31b6fc06, which
fixes a similar bug in ALTER TABLE .. ADD CONSTRAINT.

Patch by Noah Misch.

Gianni Ciolli, reviewed by Noah Misch

This isn't applicable on Windows, and the internal link to the
psql documentation should be more than sufficient.

Susanne Ebrecht

If a smart shutdown occurs just as a child is starting up, and the
child subsequently becomes a walsender, there is a race condition:
the postmaster might count the exstant backends, determine that there
is one normal backend, and wait for it to die off.  Had the walsender
transition already occurred before the postmaster counted, it would
have proceeded with the shutdown.

To fix this, have each child that transforms into a walsender kick
the postmaster just after doing so, so that the state machine is
certain to advance.

Fujii Masao

This would lead to leaking the PGconn structure after an error detected by
conninfo_array_parse(), as well as failing to return a useful error message
in such cases.  Backpatch to 9.0 where the error was introduced.

Joseph Adams

Susanne Ebrecht and me

Instead, write the unconverted output - it will be in the wrong
encoding, but at least we don't crash.

Rushabh Lathia

Shigeru Hanada, with some corrections.